diff --git a/.clangd b/.clangd
new file mode 100644
index 0000000..8ae8d15
--- /dev/null
+++ b/.clangd
@@ -0,0 +1,7 @@
+CompileFlags: {CompilationDatabase: }
+
+If:
+  PathMatch: .*\.c
+
+CompileFlags:
+  Add: [-std=gnu23, -Wall, -Wextra,  -I src/c -I src/c/arith -I src/c/environment -I src/c/io -I src/c/memory -I src/c/ops -I src/c/payloads]
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 701b16b..b6853b9 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,7 @@ TESTS := $(shell find unit-tests -name *.sh)
 
 # INC_DIRS := $(shell find $(SRC_DIRS) -type d)
 # INC_FLAGS := $(addprefix -I,$(INC_DIRS))
-INC_FLAGS := -I $(SRC_DIRS)
+INC_FLAGS := -I $(shell find $(SRC_DIRS) -type d)
 
 TMP_DIR ?= ./tmp
 
diff --git a/src/c/io/io.c b/src/c/io/io.c
index 2a897f7..61175e8 100644
--- a/src/c/io/io.c
+++ b/src/c/io/io.c
@@ -15,9 +15,9 @@
 #include <pwd.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <time.h>
 #include <unistd.h>
 #include <uuid/uuid.h>
 /*
@@ -28,7 +28,7 @@
 
 #include <curl/curl.h>
 
-//#include "arith/integer.h"
+// #include "arith/integer.h"
 #include "debug.h"
 #include "io/fopen.h"
 #include "io/io.h"
@@ -42,6 +42,8 @@
 // #include "ops/intern.h"
 // #include "ops/lispops.h"
 
+#include "ops/assoc.h"
+#include "ops/bind.h"
 #include "ops/stack_ops.h"
 #include "ops/string_ops.h"
 #include "ops/truth.h"
@@ -50,7 +52,9 @@
 #include "payloads/cons.h"
 #include "payloads/exception.h"
 #include "payloads/integer.h"
+#include "payloads/read_stream.h"
 #include "payloads/stack.h"
+#include "payloads/write_stream.h"
 
 #include "utils.h"
 
@@ -62,21 +66,36 @@
 CURLSH *io_share;
 
 /**
- * @brief bound to the Lisp string representing C_IO_IN in initialisation.
+ * @brief bound to the Lisp symbol representing C_IO_IN in initialisation.
  */
 struct pso_pointer lisp_io_in;
 /**
- * @brief bound to the Lisp string representing C_IO_OUT in initialisation.
+ * @brief bound to the Lisp symbol representing C_IO_OUT in initialisation.
  */
 struct pso_pointer lisp_io_out;
 
-
 /**
  * Allow a one-character unget facility. This may not be enough - we may need
  * to allocate a buffer.
  */
 wint_t ungotten = 0;
 
+/**
+ * given this file handle f, return a new url_file handle wrapping it.
+ *
+ * @param f the file to be wrapped;
+ * @return the new handle, or null if no such handle could be allocated.
+ */
+URL_FILE *file_to_url_file( FILE *f ) {
+    URL_FILE *result = ( URL_FILE * ) malloc( sizeof( URL_FILE ) );
+
+    if ( result != NULL ) {
+        result->type = CFTYPE_FILE, result->handle.file = f;
+    }
+
+    return result;
+}
+
 /**
  * Initialise the I/O subsystem.
  *
@@ -99,6 +118,32 @@ int initialise_io(  ) {
     return result;
 }
 
+struct pso_pointer initialise_default_streams( struct pso_pointer env ) {
+    lisp_io_in = c_string_to_lisp_symbol( C_IO_IN );
+    lisp_io_out = c_string_to_lisp_symbol( C_IO_OUT );
+
+    env = c_bind( lisp_io_in,
+                  make_read_stream( file_to_url_file( stdin ),
+                                    c_cons( c_cons
+                                            ( c_string_to_lisp_keyword
+                                              ( L"url" ),
+                                              c_string_to_lisp_string
+                                              ( L"system:standard input" ) ),
+                                            nil ) ), env );
+    if ( !nilp( env ) && !exceptionp( env ) ) {
+        env = c_bind( lisp_io_out,
+                      make_write_stream( file_to_url_file( stdout ),
+                                         c_cons( c_cons
+                                                 ( c_string_to_lisp_keyword
+                                                   ( L"url" ),
+                                                   c_string_to_lisp_string
+                                                   ( L"system:standard input" ) ),
+                                                 nil ) ), env );
+    }
+
+    return env;
+}
+
 /**
  * Convert this lisp string-like-thing (also works for symbols, and, later
  * keywords) into a UTF-8 string. NOTE that the returned value has been
@@ -138,24 +183,6 @@ char *lisp_string_to_c_string( struct pso_pointer s ) {
     return result;
 }
 
-
-/**
- * given this file handle f, return a new url_file handle wrapping it.
- *
- * @param f the file to be wrapped;
- * @return the new handle, or null if no such handle could be allocated.
- */
-URL_FILE *file_to_url_file( FILE *f ) {
-    URL_FILE *result = ( URL_FILE * ) malloc( sizeof( URL_FILE ) );
-
-    if ( result != NULL ) {
-        result->type = CFTYPE_FILE, result->handle.file = f;
-    }
-
-    return result;
-}
-
-
 /**
  * get one wide character from the buffer.
  *
@@ -193,13 +220,15 @@ wint_t url_fgetwc( URL_FILE *input ) {
                     debug_printf( DEBUG_IO, 0,
                                   L"url_fgetwc: cbuff is '%s'; (first) character = %d (%c)\n",
                                   cbuff, c, c & 0xf7 );
-                    /* The value of each individual byte indicates its UTF-8 function, as follows:
+                    /* The value of each individual byte indicates its UTF-8 function,
+                     * as follows:
                      *
                      * 00 to 7F hex (0 to 127): first and only byte of a sequence.
-                     * 80 to BF hex (128 to 191): continuing byte in a multi-byte sequence.
-                     * C2 to DF hex (194 to 223): first byte of a two-byte sequence.
-                     * E0 to EF hex (224 to 239): first byte of a three-byte sequence.
-                     * F0 to FF hex (240 to 255): first byte of a four-byte sequence.
+                     * 80 to BF hex (128 to 191): continuing byte in a multi-byte
+                     * sequence. C2 to DF hex (194 to 223): first byte of a two-byte
+                     * sequence. E0 to EF hex (224 to 239): first byte of a three-byte
+                     * sequence. F0 to FF hex (240 to 255): first byte of a four-byte
+                     * sequence.
                      */
                     if ( c <= 0xf7 ) {
                         count = 1;
@@ -219,8 +248,7 @@ wint_t url_fgetwc( URL_FILE *input ) {
 
                     free( wbuff );
                     free( cbuff );
-                }
-                break;
+                } break;
             case CFTYPE_NONE:
                 break;
         }
@@ -265,8 +293,8 @@ struct pso_pointer get_character( struct pso_pointer read_stream ) {
     if ( readp( read_stream ) ) {
         result =
             make_character( url_fgetwc
-                            ( pointer_to_object_of_size_class
-                              ( read_stream, 2 )->payload.stream.stream ) );
+                            ( pointer_to_object_of_size_class( read_stream, 2 )
+                              ->payload.stream.stream ) );
     }
 
     return result;
@@ -286,8 +314,8 @@ struct pso_pointer push_back_character( struct pso_pointer c,
 
     if ( characterp( c ) && readp( r ) ) {
         if ( url_ungetwc( ( wint_t )
-                          ( pointer_to_object( c )->payload.
-                            character.character ),
+                          ( pointer_to_object( c )->payload.character.
+                            character ),
                           pointer_to_object( r )->payload.stream.stream ) >=
              0 ) {
             result = t;
@@ -308,16 +336,14 @@ struct pso_pointer push_back_character( struct pso_pointer c,
  * @param env my environment.
  * @return T if the stream was successfully closed, else nil.
  */
-struct pso_pointer
-lisp_close( struct pso_pointer frame_pointer, struct pso_pointer env ) {
+struct pso_pointer lisp_close( struct pso_pointer frame_pointer,
+                               struct pso_pointer env ) {
     struct pso4 *frame = pointer_to_pso4( frame_pointer );
     struct pso_pointer result = nil;
 
     if ( readp( fetch_arg( frame, 0 ) ) || writep( fetch_arg( frame, 0 ) ) ) {
-        if ( url_fclose
-             ( pointer_to_object( fetch_arg( frame, 0 ) )->payload.stream.
-               stream )
-             == 0 ) {
+        if ( url_fclose( pointer_to_object( fetch_arg( frame, 0 ) )
+                         ->payload.stream.stream ) == 0 ) {
             result = t;
         }
     }
@@ -328,8 +354,9 @@ lisp_close( struct pso_pointer frame_pointer, struct pso_pointer env ) {
 struct pso_pointer add_meta_integer( struct pso_pointer meta, wchar_t *key,
                                      long int value ) {
     return
-        c_cons( c_cons( c_string_to_lisp_keyword( key ),
-                        make_integer( value ) ), meta );
+        c_cons( c_cons
+                ( c_string_to_lisp_keyword( key ), make_integer( value ) ),
+                meta );
 }
 
 struct pso_pointer add_meta_string( struct pso_pointer meta, wchar_t *key,
@@ -338,8 +365,10 @@ struct pso_pointer add_meta_string( struct pso_pointer meta, wchar_t *key,
     wchar_t buffer[strlen( value ) + 1];
     mbstowcs( buffer, value, strlen( value ) + 1 );
 
-    return c_cons( c_cons( c_string_to_lisp_keyword( key ),
-                           c_string_to_lisp_string( buffer ) ), meta );
+    return
+        c_cons( c_cons
+                ( c_string_to_lisp_keyword( key ),
+                  c_string_to_lisp_string( buffer ) ), meta );
 }
 
 struct pso_pointer add_meta_time( struct pso_pointer meta, wchar_t *key,
@@ -348,9 +377,8 @@ struct pso_pointer add_meta_time( struct pso_pointer meta, wchar_t *key,
      * bit of an oversight! */
     char datestring[256];
 
-    strftime( datestring,
-              sizeof( datestring ),
-              nl_langinfo( D_T_FMT ), localtime( value ) );
+    strftime( datestring, sizeof( datestring ), nl_langinfo( D_T_FMT ),
+              localtime( value ) );
 
     return add_meta_string( meta, key, datestring );
 }
@@ -386,8 +414,8 @@ static size_t write_meta_callback( char *string, size_t size, size_t nmemb,
     //             add_meta_string( cell->payload.stream.meta, wname, value );
 
     //         debug_printf( DEBUG_IO,
-    //                       L"write_meta_callback: added header '%s': value '%s'\n",
-    //                       name, value );
+    //                       L"write_meta_callback: added header '%s': value
+    //                       '%s'\n", name, value );
     //     } else if ( strncmp( "HTTP", s, 4 ) == 0 ) {
     //         int offset = index_of( ' ', s );
     //         char *value = trim( &s[offset] );
@@ -400,16 +428,17 @@ static size_t write_meta_callback( char *string, size_t size, size_t nmemb,
     //                                                                  10 ) );
 
     //         debug_printf( DEBUG_IO,
-    //                       L"write_meta_callback: added header 'status': value '%s'\n",
-    //                       value );
+    //                       L"write_meta_callback: added header 'status': value
+    //                       '%s'\n", value );
     //     } else {
     //         debug_printf( DEBUG_IO,
-    //                       L"write_meta_callback: header passed with no colon: '%s'\n",
-    //                       s );
+    //                       L"write_meta_callback: header passed with no colon:
+    //                       '%s'\n", s );
     //     }
     // } else {
     //     debug_print
-    //         ( L"Pointer passed to write_meta_callback did not point to a stream: ",
+    //         ( L"Pointer passed to write_meta_callback did not point to a
+    //         stream: ",
     //           DEBUG_IO );
     //     debug_dump_object( stream, DEBUG_IO );
     // }
@@ -471,13 +500,28 @@ void collect_meta( struct pso_pointer stream, char *url ) {
  */
 struct pso_pointer get_default_stream( bool inputp, struct pso_pointer env ) {
     struct pso_pointer result = nil;
-    // struct pso_pointer stream_name = inputp ? lisp_io_in : lisp_io_out;
+    struct pso_pointer stream_name = inputp ? lisp_io_in : lisp_io_out;
 
-    // result = c_assoc( stream_name, env );
+    result = c_assoc( stream_name, env );
 
     return result;
 }
 
+/**
+ * @brief if `s` points to either an input or an output stream, return the
+ * URL_FILE pointer underlying that stream, else NULL.
+ */
+URL_FILE *stream_get_url_file( struct pso_pointer s ) {
+    URL_FILE *result = NULL;
+
+    if ( readp( s ) || writep( s ) ) {
+        struct pso2 *obj = pointer_to_object( s );
+
+        result = obj->payload.stream.stream;
+    }
+
+    return result;
+}
 
 /**
  * Function: return a stream open on the URL indicated by the first argument;
@@ -494,8 +538,8 @@ struct pso_pointer get_default_stream( bool inputp, struct pso_pointer env ) {
  * @return a string of one character, namely the next available character
  * on my stream, if any, else nil.
  */
-struct pso_pointer
-lisp_open( struct pso_pointer frame_pointer, struct pso_pointer env ) {
+struct pso_pointer lisp_open( struct pso_pointer frame_pointer,
+                              struct pso_pointer env ) {
     struct pso4 *frame = pointer_to_pso4( frame_pointer );
     struct pso_pointer result = nil;
 
@@ -505,10 +549,10 @@ lisp_open( struct pso_pointer frame_pointer, struct pso_pointer env ) {
     //     if ( nilp( fetch_arg( frame, 1) ) ) {
     //         URL_FILE *stream = url_fopen( url, "r" );
 
-    //         debug_printf( DEBUG_IO, 0, 
-    //                       L"lisp_open: stream @ %ld, stream type = %d, stream handle = %ld\n",
-    //                       ( long int ) &stream, ( int ) stream->type,
-    //                       ( long int ) stream->handle.file );
+    //         debug_printf( DEBUG_IO, 0,
+    //                       L"lisp_open: stream @ %ld, stream type = %d, stream
+    //                       handle = %ld\n", ( long int ) &stream, ( int )
+    //                       stream->type, ( long int ) stream->handle.file );
 
     //         switch ( stream->type ) {
     //             case CFTYPE_NONE:
@@ -561,16 +605,16 @@ lisp_open( struct pso_pointer frame_pointer, struct pso_pointer env ) {
  * @return a string of one character, namely the next available character
  * on my stream, if any, else nil.
  */
-struct pso_pointer
-lisp_read_char( struct pso_pointer frame_pointer, struct pso_pointer env ) {
+struct pso_pointer lisp_read_char( struct pso_pointer frame_pointer,
+                                   struct pso_pointer env ) {
     struct pso4 *frame = pointer_to_pso4( frame_pointer );
     struct pso_pointer result = nil;
 
-    if ( readp( fetch_arg( frame, 0 ) ) ) {
+    struct pso_pointer stream_pointer = fetch_arg( frame, 0 );
+    if ( readp( stream_pointer ) ) {
         result =
-            make_string( url_fgetwc
-                         ( pointer_to_object( fetch_arg( frame, 0 ) )->
-                           payload.stream.stream ), nil );
+            make_string( url_fgetwc( stream_get_url_file( stream_pointer ) ),
+                         nil );
     }
 
     return result;
@@ -590,14 +634,13 @@ lisp_read_char( struct pso_pointer frame_pointer, struct pso_pointer env ) {
  * @return a string of one character, namely the next available character
  * on my stream, if any, else nil.
  */
-struct pso_pointer
-lisp_slurp( struct pso_pointer frame_pointer, struct pso_pointer env ) {
+struct pso_pointer lisp_slurp( struct pso_pointer frame_pointer,
+                               struct pso_pointer env ) {
     struct pso4 *frame = pointer_to_pso4( frame_pointer );
     struct pso_pointer result = nil;
 
     if ( readp( fetch_arg( frame, 0 ) ) ) {
-        URL_FILE *stream =
-            pointer_to_object( fetch_arg( frame, 0 ) )->payload.stream.stream;
+        URL_FILE *stream = stream_get_url_file( fetch_arg( frame, 0 ) );
         struct pso_pointer cursor = make_string( url_fgetwc( stream ), nil );
         result = cursor;
 
diff --git a/src/c/io/io.h b/src/c/io/io.h
index 703ed2e..995f508 100644
--- a/src/c/io/io.h
+++ b/src/c/io/io.h
@@ -19,6 +19,7 @@
 extern CURLSH *io_share;
 
 int initialise_io(  );
+struct pso_pointer initialise_default_streams( struct pso_pointer env );
 
 #define C_IO_IN L"*in*"
 #define C_IO_OUT L"*out*"
@@ -37,6 +38,8 @@ struct pso_pointer push_back_character( struct pso_pointer c,
 
 struct pso_pointer get_default_stream( bool inputp, struct pso_pointer env );
 
+URL_FILE *stream_get_url_file( struct pso_pointer s );
+
 struct pso_pointer
 lisp_close( struct pso_pointer frame_pointer, struct pso_pointer env );
 struct pso_pointer
diff --git a/src/c/io/print.h b/src/c/io/print.h
index 0a969e0..39b7d41 100644
--- a/src/c/io/print.h
+++ b/src/c/io/print.h
@@ -14,6 +14,7 @@
 #ifndef __psse_io_print_h
 #define __psse_io_print_h
 
+#include "io/fopen.h"
 struct pso_pointer c_print( struct pso_pointer p, struct pso_pointer stream );
 
 struct pso_pointer in_print( struct pso_pointer p, URL_FILE * output );
diff --git a/src/c/io/read.c b/src/c/io/read.c
index f072a6d..f78e796 100644
--- a/src/c/io/read.c
+++ b/src/c/io/read.c
@@ -32,6 +32,7 @@
 #include "memory/pso2.h"
 #include "memory/tags.h"
 
+#include "payloads/function.h"
 #include "payloads/integer.h"
 #include "payloads/read_stream.h"
 
@@ -41,7 +42,7 @@
 #include "ops/string_ops.h"
 #include "ops/truth.h"
 
-// TODO: what I've copied from 0.0.6 is *wierdly* over-complex for just now.
+// TODO: what I've copied from 0.0.6 is *weirdly* over-complex for just now.
 // I think I'm going to essentially delete all this and start again. We need
 // to be able to despatch on readttables, and the initial readtable functions
 // don't need to be written in Lisp.
@@ -55,9 +56,9 @@
 // the next is the input stream; the next is the readtable, if any.
 
 /*
- * for the time being things which may be read are: 
+ * for the time being things which may be read are:
  * * integers
- * * lists 
+ * * lists
  * * atoms
  * * dotted pairs
  */
@@ -72,8 +73,12 @@
  * 1. The read table currently in use;
  * 2. The character most recently read from that stream.
  */
-struct pso_pointer read_example( struct pso_pointer frame_pointer,
-                                 struct pso_pointer env ) {
+struct pso_pointer read_example(
+#ifndef MANAGED_POINTER_ONLY
+                                    struct pso4 *frame,
+#endif
+                                    struct pso_pointer frame_pointer,
+                                    struct pso_pointer env ) {
     struct pso4 *frame = pointer_to_pso4( frame_pointer );
     struct pso_pointer stream = fetch_arg( frame, 0 );
     struct pso_pointer readtable = fetch_arg( frame, 1 );
@@ -93,8 +98,12 @@ struct pso_pointer read_example( struct pso_pointer frame_pointer,
  * 1. The read table currently in use;
  * 2. The character most recently read from that stream.
  */
-struct pso_pointer read_number( struct pso_pointer frame_pointer,
-                                struct pso_pointer env ) {
+struct pso_pointer read_number(
+#ifndef MANAGED_POINTER_ONLY
+                                   struct pso4 *frame,
+#endif
+                                   struct pso_pointer frame_pointer,
+                                   struct pso_pointer env ) {
     struct pso4 *frame = pointer_to_pso4( frame_pointer );
     struct pso_pointer stream = fetch_arg( frame, 0 );
     struct pso_pointer readtable = fetch_arg( frame, 1 );
@@ -109,8 +118,8 @@ struct pso_pointer read_number( struct pso_pointer frame_pointer,
         if ( nilp( character ) ) {
             character = get_character( stream );
         }
-        wchar_t c = nilp( character ) ? 0 :
-            pointer_to_object( character )->payload.character.character;
+        wchar_t c = nilp( character )
+            ? 0 : pointer_to_object( character )->payload.character.character;
 
         URL_FILE *input = pointer_to_object( stream )->payload.stream.stream;
         for ( ; iswdigit( c ); c = url_fgetwc( input ) ) {
@@ -124,8 +133,12 @@ struct pso_pointer read_number( struct pso_pointer frame_pointer,
     return result;
 }
 
-struct pso_pointer read_symbol( struct pso_pointer frame_pointer,
-                                struct pso_pointer env ) {
+struct pso_pointer read_symbol(
+#ifndef MANAGED_POINTER_ONLY
+                                   struct pso4 *frame,
+#endif
+                                   struct pso_pointer frame_pointer,
+                                   struct pso_pointer env ) {
     struct pso4 *frame = pointer_to_pso4( frame_pointer );
     struct pso_pointer stream = fetch_arg( frame, 0 );
     struct pso_pointer readtable = fetch_arg( frame, 1 );
@@ -137,8 +150,8 @@ struct pso_pointer read_symbol( struct pso_pointer frame_pointer,
             character = get_character( stream );
         }
 
-        wchar_t c = nilp( character ) ? 0 :
-            pointer_to_object( character )->payload.character.character;
+        wchar_t c = nilp( character )
+            ? 0 : pointer_to_object( character )->payload.character.character;
 
         URL_FILE *input = pointer_to_object( stream )->payload.stream.stream;
         for ( ; iswalnum( c ); c = url_fgetwc( input ) ) {
@@ -163,8 +176,12 @@ struct pso_pointer read_symbol( struct pso_pointer frame_pointer,
  * 1. The read table currently in use;
  * 2. The character most recently read from that stream.
  */
-struct pso_pointer read( struct pso_pointer frame_pointer,
-                         struct pso_pointer env ) {
+struct pso_pointer read(
+#ifndef MANAGED_POINTER_ONLY
+                            struct pso4 *frame,
+#endif
+                            struct pso_pointer frame_pointer,
+                            struct pso_pointer env ) {
     struct pso4 *frame = pointer_to_pso4( frame_pointer );
     struct pso_pointer stream = fetch_arg( frame, 0 );
     struct pso_pointer readtable = fetch_arg( frame, 1 );
@@ -201,27 +218,38 @@ struct pso_pointer read( struct pso_pointer frame_pointer,
                 /* skip all characters from semi-colon to the end of the line */
                 break;
             case EOF:
-//                result = throw_exception( c_string_to_lisp_symbol( L"read" ),
-//                                          c_string_to_lisp_string
-//                                          ( L"End of input while reading" ),
-//                                          frame_pointer );
+                //                result = throw_exception( c_string_to_lisp_symbol(
+                //                L"read" ),
+                //                                          c_string_to_lisp_string
+                //                                          ( L"End of input while
+                //                                          reading" ),
+                //                                          frame_pointer );
                 break;
             default:
-                struct pso_pointer next =
-                    make_frame( 3, frame_pointer, stream, readtable,
-                                make_character( c ) );
+                struct pso_pointer next = make_frame( 3, frame_pointer, stream,
+                                                      readtable,
+                                                      make_character( c ) );
                 inc_ref( next );
                 if ( iswdigit( c ) ) {
                     result = read_number( next, env );
                 } else if ( iswalpha( c ) ) {
                     result = read_symbol( next, env );
                 } else {
-//                    result =
-//                        throw_exception( c_string_to_lisp_symbol( L"read" ),
-//                                         make_cons( c_string_to_lisp_string
-//                                                    ( L"Unrecognised start of input character" ),
-//                                                    make_string( c, NIL ) ),
-//                                         frame_pointer );
+                    //                    result =
+                    //                        throw_exception(
+                    //                        c_string_to_lisp_symbol( L"read" ),
+                    //                                         make_cons(
+                    //                                         c_string_to_lisp_string
+                    //                                                    (
+                    //                                                    L"Unrecognised
+                    //                                                    start of
+                    //                                                    input
+                    //                                                    character"
+                    //                                                    ),
+                    //                                                    make_string(
+                    //                                                    c, NIL )
+                    //                                                    ),
+                    //                                         frame_pointer );
                 }
                 dec_ref( next );
                 break;
diff --git a/src/c/memory/node.c b/src/c/memory/node.c
index 5bac51d..42638a7 100644
--- a/src/c/memory/node.c
+++ b/src/c/memory/node.c
@@ -8,14 +8,20 @@
  *  Licensed under GPL version 2.0, or, at your option, any later version.
  */
 
-#include "node.h"
-
 #include <bits/stdint-uintn.h>
 
 #include "environment/environment.h"
+
+#include "io/io.h"
+
 #include "memory/memory.h"
 #include "memory/pointer.h"
+#include "memory/tags.h"
+
 #include "ops/eq.h"
+#include "ops/string_ops.h"
+#include "ops/truth.h"
+#include "payloads/exception.h"
 
 /**
  * @brief Flag to prevent the node being initialised more than once.
@@ -63,5 +69,16 @@ struct pso_pointer initialise_node( uint32_t index ) {
 
     struct pso_pointer result = initialise_environment( index );
 
+    if ( !nilp( result ) && !exceptionp( result ) ) {
+        if ( initialise_io(  ) == 0 ) {
+            result = initialise_default_streams( result );
+        } else {
+            result =
+                make_exception( c_string_to_lisp_string
+                                ( L"Failed to initialise default streams" ),
+                                nil, nil, nil );
+        }
+    }
+
     return result;
 }
diff --git a/src/c/memory/node.h b/src/c/memory/node.h
index 5ce48cf..d8559f1 100644
--- a/src/c/memory/node.h
+++ b/src/c/memory/node.h
@@ -33,6 +33,6 @@ extern struct pso_pointer t;
 
 extern struct pso_pointer oblist;
 
-struct pso_pointer initialise_node( uint32_t index );
+struct pso_pointer initialise_node( int node_index );
 
 #endif
diff --git a/src/c/ops/bind.c b/src/c/ops/bind.c
index ba25834..5d66359 100644
--- a/src/c/ops/bind.c
+++ b/src/c/ops/bind.c
@@ -19,6 +19,7 @@
 #include "ops/stack_ops.h"
 
 #include "payloads/cons.h"
+#include "payloads/function.h"
 #include "payloads/stack.h"
 
 struct pso_pointer lisp_bind(
diff --git a/src/c/ops/bind.h b/src/c/ops/bind.h
index 517086a..2682fe8 100644
--- a/src/c/ops/bind.h
+++ b/src/c/ops/bind.h
@@ -3,7 +3,7 @@
  *
  *  Post Scarcity Software Environment: bind.
  *
- *  Test for pointer binduality.
+ *  Bind a name to a value in a store.
  *
  *  (c) 2026 Simon Brooke <simon@journeyman.cc>
  *  Licensed under GPL version 2.0, or, at your option, any later version.
diff --git a/src/c/ops/eval_apply.c b/src/c/ops/eval_apply.c
index aeb3577..9333a03 100644
--- a/src/c/ops/eval_apply.c
+++ b/src/c/ops/eval_apply.c
@@ -23,6 +23,7 @@
 #include "ops/truth.h"
 
 #include "payloads/cons.h"
+#include "payloads/function.h"
 #include "payloads/stack.h"
 
 /**
diff --git a/src/c/ops/list_ops.h b/src/c/ops/list_ops.h
index ae770cd..0121b57 100644
--- a/src/c/ops/list_ops.h
+++ b/src/c/ops/list_ops.h
@@ -15,6 +15,8 @@
 #include "memory/pointer.h"
 #include "memory/pso4.h"
 
+#include "payloads/function.h"
+
 struct pso_pointer car(
 #ifndef MANAGED_POINTER_ONLY
                            struct pso4 *frame,
diff --git a/src/c/ops/repl.c b/src/c/ops/repl.c
new file mode 100644
index 0000000..efc8a3b
--- /dev/null
+++ b/src/c/ops/repl.c
@@ -0,0 +1,90 @@
+/**
+ * repl.c
+ *
+ * Post Scarcity Soctware Environment
+ *
+ * First cut at a top level read-eval-print loop.
+ *
+ * Copyright (c): 17 Apr 2026 Simon Brooke <simon@journeyman.cc>
+ * Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#include <signal.h>
+#include <stdio.h>
+#include <wchar.h>
+
+#include "debug.h"
+
+#include "io/fopen.h"
+#include "io/io.h"
+#include "io/print.h"
+#include "io/read.h"
+
+#include "memory/node.h"
+#include "memory/pointer.h"
+#include "memory/pso.h"
+#include "memory/pso2.h"
+#include "memory/pso2.h"
+#include "memory/pso2.h"
+#include "memory/pso2.h"
+#include "memory/pso4.h"
+#include "memory/tags.h"
+
+#include "payloads/cons.h"
+#include "payloads/function.h"
+#include "payloads/stack.h"
+
+#include "ops/assoc.h"
+#include "ops/eval_apply.h"
+#include "ops/truth.h"
+
+/**
+ * @brief Handle an interrupt signal.
+ *
+ * @param dummy
+ */
+void int_handler( int dummy ) {
+    wprintf( L"TODO: handle ctrl-C in a more interesting way\n" );
+}
+
+/**
+ * Very simple read/eval/print loop for bootstrapping.
+ */
+void c_repl(  ) {
+    signal( SIGINT, int_handler );
+    debug_print( L"Entered repl\n", DEBUG_REPL, 0 );
+
+    struct pso_pointer env = consp( oblist ) ? oblist : c_cons( oblist, nil );
+    struct pso_pointer input_stream = c_assoc( lisp_io_in, env );
+    struct pso_pointer output_stream = c_assoc( lisp_io_out, env );
+
+    while ( readp( input_stream )
+            && !url_feof( stream_get_url_file( input_stream ) ) ) {
+        /* bottom of stack */
+        struct pso_pointer frame_pointer = make_frame( 1, nil, input_stream );
+
+        if ( nilp( frame_pointer ) )
+            break;
+        struct pso_pointer input = read(
+#ifndef MANAGED_POINTER_ONLY
+                                            pointer_to_pso4( frame_pointer ),
+#endif
+                                            frame_pointer, env );
+
+        frame_pointer = make_frame( 1, frame_pointer, input );
+        if ( nilp( frame_pointer ) )
+            break;
+
+        struct pso_pointer result = eval(
+#ifndef MANAGED_POINTER_ONLY
+                                             pointer_to_pso4( frame_pointer ),
+#endif
+                                             frame_pointer, oblist );
+
+        c_print( result, output_stream );
+
+        dec_ref( frame_pointer );
+    }
+
+    debug_print( L"Leaving repl\n", DEBUG_REPL, 0 );
+}
diff --git a/src/c/ops/repl.h b/src/c/ops/repl.h
index e5b1a9a..6706539 100644
--- a/src/c/ops/repl.h
+++ b/src/c/ops/repl.h
@@ -1,15 +1,20 @@
 /**
- *  ops/repl.h
+ * repl.h
  *
- *  The read/eval/print loop.
+ * Post Scarcity Soctware Environment
  *
- *  (c) 2026 Simon Brooke <simon@journeyman.cc>
- *  Licensed under GPL version 2.0, or, at your option, any later version.
+ * Read/Eval/Print loop
+ * 
+ * Copyright (c): 17 Apr 2026 Simon Brooke <simon@journeyman.cc>
+ * Licensed under GPL version 2.0, or, at your option, any later version.
  */
 
-#ifndef __psse_ops_repl_h
-#define __psse_ops_repl_h
+#ifndef SRC_C_OPS_REPL_H_
+#define SRC_C_OPS_REPL_H_
 
-// struct pso_pointer repl( struct pso_pointer prompt, struct pso_pointer readtable);
 
-#endif
+
+void c_repl(  );
+
+
+#endif /* SRC_C_OPS_REPL_H_ */
diff --git a/src/c/payloads/read_stream.c b/src/c/payloads/read_stream.c
index 995d454..a0b0876 100644
--- a/src/c/payloads/read_stream.c
+++ b/src/c/payloads/read_stream.c
@@ -1,5 +1,5 @@
 /**
- *  payloads/read_stream.h
+ *  payloads/read_stream.c
  *
  *  A read stream.
  *
diff --git a/src/c/payloads/write_stream.c b/src/c/payloads/write_stream.c
new file mode 100644
index 0000000..371f32c
--- /dev/null
+++ b/src/c/payloads/write_stream.c
@@ -0,0 +1,36 @@
+/**
+ *  payloads/read_stream.c
+ *
+ *  A read stream.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#include <stdio.h>
+
+#include <curl/curl.h>
+
+#include "io/fopen.h"
+#include "memory/pointer.h"
+#include "memory/pso.h"
+#include "memory/pso2.h"
+#include "memory/tags.h"
+
+
+/**
+ * Construct a cell which points to a stream open for writing.
+ * @param input the C stream to wrap.
+ * @param metadata a pointer to an associaton containing metadata on the stream.
+ * @return a pointer to the new read stream.
+ */
+struct pso_pointer make_write_stream( URL_FILE *output,
+                                      struct pso_pointer metadata ) {
+    struct pso_pointer pointer = allocate( WRITETAG, 2 );
+    struct pso2 *cell = pointer_to_object( pointer );
+
+    cell->payload.stream.stream = output;
+    cell->payload.stream.meta = metadata;
+
+    return pointer;
+}
diff --git a/src/c/payloads/write_stream.h b/src/c/payloads/write_stream.h
index d647575..69de8a4 100644
--- a/src/c/payloads/write_stream.h
+++ b/src/c/payloads/write_stream.h
@@ -11,4 +11,8 @@
 #define __psse_payloads_write_stream_h
 
 /* write stream shares a payload with /see read_streem.h */
+
+#include "io/fopen.h"
+struct pso_pointer make_write_stream( URL_FILE * output,
+                                      struct pso_pointer metadata );
 #endif
diff --git a/src/c/psse.c b/src/c/psse.c
index 0c36395..cd9b092 100644
--- a/src/c/psse.c
+++ b/src/c/psse.c
@@ -20,10 +20,12 @@
 #include "debug.h"
 #include "psse.h"
 #include "io/io.h"
+
 #include "memory/node.h"
 #include "memory/pso.h"
 #include "memory/tags.h"
 
+#include "ops/repl.h"
 #include "ops/stack_ops.h"
 #include "ops/truth.h"
 
@@ -65,37 +67,8 @@ void print_options( FILE *stream ) {
 #endif
 }
 
-/**
- * @brief Handle an interrupt signal.
- *
- * @param dummy
- */
-void int_handler( int dummy ) {
-    wprintf( L"TODO: handle ctrl-C in a more interesting way\n" );
-}
 
 /**
- * The read/eval/print loop.
- */
-void repl(  ) {
-    signal( SIGINT, int_handler );
-    debug_print( L"Entered repl\n", DEBUG_REPL, 0 );
-
-    struct pso_pointer env = consp( oblist ) ? oblist : c_cons( oblist, nil );
-
-    /* bottom of stack */
-    struct pso_pointer frame_pointer = make_frame( 1, nil, nil, env );
-
-    if ( !nilp( frame_pointer ) ) {
-//       lisp_repl( get_stack_frame( frame_pointer ), frame_pointer, env );
-
-        dec_ref( frame_pointer );
-    }
-
-    debug_print( L"Leaving repl\n", DEBUG_REPL, 0 );
-}
-
- /**
  * main entry point; parse command line arguments, initialise the environment,
  * and enter the read-eval-print loop.
  */
@@ -150,7 +123,8 @@ int main( int argc, char *argv[] ) {
         fputs( "Failed to initialise node\n", stderr );
         exit( 1 );
     }
-    // repl(  );
+
+    c_repl(  );
 
     exit( 0 );
 }
diff --git a/src/templates/codetemplates.xml b/src/templates/codetemplates.xml
new file mode 100644
index 0000000..7140a04
--- /dev/null
+++ b/src/templates/codetemplates.xml
@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?><templates><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.constructorcomment_context" deleted="false" description="Comment for created constructors" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.constructorcomment" name="constructorcomment">/*
+ *
+ */</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.destructorcomment_context" deleted="false" description="Comment for created destructors" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.destructorcomment" name="destructorcomment">/*
+ *
+ */</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.filecomment_context" deleted="false" description="Comment for created C/C++ files" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.filecomment" name="filecomment">/**
+ * ${file_name}
+ *
+ * ${project_name}
+ *
+ * TODO: Edit purpose.
+ * 
+ * Copyright (c): ${date} Simon Brooke &lt;simon@journeyman.cc&gt;
+ * Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.typecomment_context" deleted="false" description="Comment for created classes" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.typecomment" name="typecomment">/*
+ *
+ */</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.fieldcomment_context" deleted="false" description="Comment for fields" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.fieldcomment" name="fieldcomment">/*
+ *
+ */</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.methodcomment_context" deleted="false" description="Comment for methods" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.methodcomment" name="methodcomment">/*
+ *
+ */</template><template autoinsert="true" context="org.eclipse.cdt.core.cxxSource.contenttype_context" deleted="false" description="Default template for newly created C++ source files" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.cppsourcefile" name="Default C++ source template">${filecomment}
+${includes}
+
+${namespace_begin}
+
+${declarations}
+
+${namespace_end}</template><template autoinsert="true" context="org.eclipse.cdt.core.cxxSource.contenttype_context" deleted="false" description="Default template for newly created C++ test files" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.cpptestfile" name="Default C++ test template">${filecomment}
+${includes}
+
+${namespace_begin}
+
+${declarations}
+
+${namespace_end}</template><template autoinsert="true" context="org.eclipse.cdt.core.cxxHeader.contenttype_context" deleted="false" description="Default template for newly created C++ header files" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.cppheaderfile" name="Default C++ header template">${filecomment}
+#ifndef ${include_guard_symbol}
+#define ${include_guard_symbol}
+
+${includes}
+
+${namespace_begin}
+
+${declarations}
+
+${namespace_end}
+
+#endif /* ${include_guard_symbol} */</template><template autoinsert="true" context="org.eclipse.cdt.core.cSource.contenttype_context" deleted="false" description="Default template for newly created C source files" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.csourcefile" name="Default C source template">${filecomment}
+${includes}
+
+${declarations}</template><template autoinsert="false" context="org.eclipse.cdt.core.cHeader.contenttype_context" deleted="false" description="Default template for newly created C header files" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.cheaderfile" name="Default C header template">${filecomment}
+#ifndef ${include_guard_symbol}
+#define ${include_guard_symbol}
+
+${includes}
+
+${declarations}
+
+#endif /* ${include_guard_symbol} */</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.namespace_context" deleted="false" description="Beginning of namespace declaration" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.namespace_begin" name="namespace_begin">namespace ${namespace_name} {</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.namespace_context" deleted="false" description="End of namespace declaration" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.namespace_end" name="namespace_end">} /* namespace ${namespace_name} */</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.class_context" deleted="false" description="Code in created class definitions" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.class_body" name="class_body">${declarations}</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.methodbody_context" deleted="false" description="Code in created method stubs" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.methodbody" name="methodbody">	// ${todo} Auto-generated method stub
+	${body_statement}</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.constructorbody_context" deleted="false" description="Code in created constructor stubs" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.constructorbody" name="constructorbody">	// ${todo} Auto-generated constructor stub
+	${body_statement}</template><template autoinsert="true" context="org.eclipse.cdt.ui.text.codetemplates.destructorbody_context" deleted="false" description="Code in created destructor stubs" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.destructorbody" name="destructorbody">	${body_statement}
+	// ${todo} Auto-generated destructor stub</template><template autoinsert="true" context="org.eclipse.cdt.core.asmSource.contenttype_context" deleted="false" description="Default template for newly created assembly files" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.asmsourcefile" name="Default assembly template">${filecomment}
+</template><template autoinsert="true" context="org.eclipse.core.runtime.text.contenttype_context" deleted="false" description="Default template for newly created text files" enabled="true" id="org.eclipse.cdt.ui.text.codetemplates.textfile" name="Default text file template">${file_name}
+ Created on: ${date}
+     Author: ${user}
+
+</template></templates>